Mobile and landline/wireline computing devices have in recent years become a valuable tool in day-to-day communications. Desktop computers, workstations, and other wireline computers currently allow users to communicate via e-mail, video conferencing, and instant messaging (IM) to name a few communication applications. Mobile devices, such as mobile telephones, handheld computers, personal digital assistants (PDAs), etc. also assist in day-to-day communication. Mobile/wireless telephones have conventionally served as voice communication devices, but through technological advancements have recently proved to be effective devices for communicating data, graphics, etc. Wireless and landline technologies continue to merge into a more unified communication system, as user demand for seamless communications across different platforms increases.
Many communication applications allow for real-time or near real-time communication that falls outside of the traditional voice communication associated with wireline and wireless telephone communications. Chat sessions, instant messaging, Short Message Service (SMS), video conferencing, are but a few such communication vehicles. Many of these types of communications have been well-received by the communicating public, and are expected to become increasingly popular, particularly in view of the proliferation of wireless devices and continual technological breakthroughs.
In order to implement such technologies, “presence” technology is used to determine the location, willingness to communicate, and other parameters relating to real-time or near real-time communications. Presence technology generally refers to applications and services that facilitate location and identification of one or more endpoints to such communication links. For example, if a user of a wireless, handheld device would like to initiate an IM session with another IM user, presence services may be used to present users' willingness to receive IM messages. Presence services are an integral part of third generation (3G) wireless networks, and are intended to be employed across a wide variety of communication devices.
Current presence service technology includes the concepts of presentities, presence servers, and watchers. Generally, a presentity can provide information as to its “presence” (e.g., location, willingness to communicate at a certain time or with certain users, etc.). This information can be collected and utilized by presence servers, that can notify authorized “watchers” who are interested in presence information that certain presence information is available. Watcher applications may be implemented in wireline and wireless terminals to obtain presence information from the presence servers about other users. This may come in the form of a notification, issued to the watcher by the presence server.
Conventionally, notifications to users/watchers that a targeted user/device has become available have been sent as complete presence information. In other words, there are a number of different pieces of presence information that are associated with the totality of the presence information, and original or updated notifications result in sending all of the presence information to the notification-subscribing users who are “watching” for the particular presence information. For example, in current IETF presence format specifications such as the Common Profile for Instant Messaging (CPIM) Presence Information Data Format (PIDF), all presence information is sent regardless of whether portions of the information being sent are already available to the watcher. In some environments, such as wireless environments, sending all of the presence information when only some portion of the information has changed may not be a favorable option, as the available bandwidth is typically significantly lower than in a fixed Internet environment.
Existing presence specifications do not provide any indication whether some data received earlier has become invalid. This can occur where, for example, watchers change filtering information, presentities change presence authorization levels, and presence attributes become unavailable on networks. Furthermore, the existing specifications do not provide versioning information, which is needed if presence information is delivered using multiple application protocols, because protocol-specific versioning mechanisms cannot be used in such instances.
Accordingly, there is a need in the communications industry for a more efficient and convenient manner of providing presence information. The present invention fulfills these and other needs, and offers other advantages over the prior art.